openssh: fix CVE-2024-6387

openssh: fix CVE-2024-6387

sshd(8) in Portable OpenSSH versions 8.5p1 to 9.7p1 (inclusive).
Race condition resulting in potential remote code execution.
A race condition in sshd(8) could allow remote code execution as root on non-OpenBSD systems.
This attack could be prevented by disabling the login grace timeout (LoginGraceTime=0 in sshd_config)
though this makes denial-of service against sshd(8) considerably easier.
For more information, please refer to the release notes [1] and the
report from the Qualys Security Advisory Team [2] who discovered the bug.

[1] https://www.openssh.com/txt/release-9.8
[2] https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt

References:
https://www.openssh.com/security.html

Signed-off-by: Jose Quaresma <jose.quaresma@foundries.io>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>